Experiments were undertaken to evaluate testing procedures concerned with detoxification of aflatoxin in foods and feedstuffs. Specific experiments were undertaken to ascertain: (1) the percent decrease in the fluorescence of aflatoxin B1 when chemically treated with increasing amounts of NaOH, NaOCl, and NH4OH, (2) the toxicity of native and detoxified aflatoxin B1 (3) any influence the detoxified molecule may have on the toxicity of the native molecule, (4) changes in the mutagenicity of detoxified aflatoxin B1 in an in vitro assay system, and (5) if the mutagenicity of aflatoxin is destroyed by base treatment. Although base treatment reduced aflatoxin B1 fluorescence by 30-95%, it would appear difficult to achieve complete detoxification of the aflatoxin molecule. Toxicity studies demonstrated an effect in which the detoxified aflatoxin molecule increased toxicity of the native molecule, in vitro studies showed that although the mutagen-icity and potential carcinogenicity of aflatoxin was greatly reduced by base treatment, it was not completely destroyed